Process for treating wood

ABSTRACT

A wood product for use as interior or exterior paneling formed by sandblasting cedar lumber employing a composition of silica and anhydrous oxalic acid for removing fungus growth thus forming recesses or holes through the lumber while at the same time brightening and bleaching the lumber to provide paneling of uniform color which closely simulates pecky tidewater cypress.

United States Patent Inventor Appl. No.

Filed Patented Assignee Edward L. Fox, Jr. Fort Lauderdale, Fla. 768,156

Oct. 16, 1968 May 25, 1971 Canadian Cedar Inc.

PROCESS FOR TREATING WOOD 7 Claims, No Drawings U.S. Cl 144/309, 161/109, 161/164 Int. Cl B27k 5/00 Field of Search 144/ 309,

309(1), 309 (20), 309 (25), 309 (26), 320; 161/109, 116, 123, 164, (Wood Digest) References Cited UNlTED STATES PATENTS 2/1891 Bryce 144/309 12/1935 Snelling 144/320 6/1942 Deskey 144/309 4/1944 Lehman 161/164 5/1963 Orth 144/309X Primary ExaminerGerlad A. Dost AttorneysClarence A. OBrien and Harvey B. Jacobson PROCESS FOR TREATING WOOD While the most desirable decorative paneling either interior or exterior is pecky tidewater cypress which not only provides a highly decorative ornamental appearance but also is stable with very little warpage or decay occurring after it has been cut into desired paneling and installed. However, the supply of such material is quite limited thus rendering the price quite high and impractical for many panel installations.

The product produced by the process and composition of this invention closely simulates pecky tidewater cypress. Cedar lumber or boards, such as Western Red Cedar is employed and as is well known, such lumber has certain fungi growth therein which softens certain areas of the wood and renders such areas more easily removable. This lumber is subjected to a sandblasting operation employing a composition of silica and oxalic acid which removes all or substantially all of the fungus growth thus leaving pockets, recesses or holes in the lumber and at the same time brightens the lumber and produces a uniform color whereby the finished product closely simulates pecky tidewater cypress and is provided with a substantially uni onn color to enable the installed paneling to be attractive in appearance, more uniform in appearance and otherwise perform all of the functions of pecky tidewater cypress.

The silica employed in the process may conveniently be of a size to pass through a l6-mesh screen with a moisture content of less than 0.5 percent moisture content, may be ungraded crystals or ground to a powder passing through a 100- to 200- mesh screen at a ratio between approximately 20 parts silica to 1 part oxalic acid by weight and 40 parts silica to 1 part oxalic acid by weight.

In practicing the present invention, cedar lumber generally within the range of 1 inch by 4 inch to 1 inch by 12 inch boards are employed as they are received from the mill. Other dimensions up to 4 inches by 12 inches or 6 inches by 12 inches may be employed. The lumber selected will be cured with the moisture content thereof generally ranging in the area of 8 percent to 10 percentalthough this is not critical to the present invention. This lumber is sandblasted on either or both surfaces thereof by conventional sandblasting equipment having a portable or movable nozzle controlled by an operator or a stationary nozzle or nozzles may be employed and the lumber conveyed under a single nozzle or between opposed noules. Preferably but not necessarily, the nozzles should be as wide as the boards being treated and the distance between the nozzles and the surfaces being treated may be varied as deemed appropriate by the operator. In some instances, it may be desirable to employ a movable and relatively narrow nozzle to provide a final sandblasting or touchup to the panels being formed.

A sandblasting composition including silica sand and anhydrous oxalic acid is employed in the sandblasting operation. The silica is approximately of a size to pass through a 16-mesh screen with a moisture content less than 0.5 percent. The preferred oxalic acid is ground crystals which will pass through a screen between 100- and 200-mesh which is substantially powder and has a weight of approximately 14 lbs. per gallon. Also, ungraded crystals may be employed which may be of different size although preferably are not over l/l6th inch in length and diameter so that the oxalic acid will be intimately comingled with the silica in substantially a homogeneous mixture when combined with the air during the sandblasting operation. The air pressure may vary but it is found that an air pressure of approximately 100 psi. is adequate for an effective sandblasting operation. Also, the silica and oxalic acid are combined in the ratio of approximately 20 to l to approximately to l by weight. This sandblasting operation will effectively brighten and bleach the lumber to provide a uniform color and at the same time remove fungus growth in the wood to leave recesses or holes in the lumber or wood. The treated material such as cedar or Western Red Cedar will have an appearance characteristic and other characteristics similar to extremely scarce pecky tidewater cypress. The treated boards may be sorted as to size and packaged or stored in any suitable manner and may be installed in various conventional manners for providing a highly decorative and attractive wall paneling or paneling for use wherever desired.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

1 claim:

1. The process of treating lumber having certain areas thereof erodible more easily than other areas comprising the steps of selecting pieces of lumber, subjecting at least one surface thereof to a sandblasting operation with the sandblasting material including a mixture of silica and anhydrous oxalic acid thereby eroding the more easily erodible areas to form recesses, pockets or holes through the lumber.

2. The process as defined in claim 1 in which the lumber selected is cedar having a thickness substantially less than the width with the sandblasting operation not only removing the more easily erodible areas but also brightening and bleaching the wood surface to provide uniform color thereto for simulating natural pecky tidewater cypress.

3. The process as defined in claim 2 in which the more easily erodible areas are defined by fungus growth in the wood.

4. The process as defined in claim 3 in which the ratio of silica to oxalic acid is within the range of approximately 20 to l to approximately 40 to l by weight.

5. The process as defined in claim 4 in which the oxalic acid is in the form of ground crystals capable of passing through a screen between and 200 mesh and the silica is capable of passing through a screen of approximately 16 mesh.

6. The process as defined in claim 5 in which the mixed silica and oxalic acid crystals impact the lumber at a speed created by approximately 100 psi. air pressure.

7. The process of treating cedar lumber having certain areas defined by fungus growth and more easily erodible than other areas comprising the step of subjecting at least one surface of the cedar lumber to a sandblasting operation in which the sandblasting maten'al consists of a substantially homogeneous mixture of silica and oxalic acid crystals in the ratio by weight within the range of 20 to l and 40 to l, the oxalic crystals being capable of passing through a screen between 100 and 200 mesh, the silica being capable of passing through a screen of approximately 16 mesh, the sandblasting operation simultaneously eroding the more easily erodible areas and brightening and bleaching the wood surface to simulate the appearance characteristics of material pecky tidewater cypress. 

2. The process as defined in claim 1 in which the lumber selected is cedar having a thickness substantially less than the width with the sandblasting operation not only removing the more easily erodible areas but also brightening and bleaching the wood surface to provide uniform color thereto for simulating natural pecky tidewater cypress.
 3. The process as defined in claim 2 in which the more easily erodible areas are defined by fungus growth in the wood.
 4. The process as defined in claim 3 in which the ratio of silica to oxalic acid is within the range of approximately 20 to 1 to approximately 40 to 1 by weight.
 5. The process as defined in claim 4 in which the oxalic acid is in the form of ground crystals capable of passing through a screen between 100 and 200 mesh and the silica is capable of passing through a screen of approximately 16 mesh.
 6. The process as defined in claim 5 in which the mixed silica and oxalic acid crystals impact the lumber at a speed created by approximately 100 p.s.i. air pressure.
 7. The process of treating cedar lumber having certain areas defined by fungus growth and more easily erodible than other areas comprising the step of subjecting at least one surface of the cedar lumber to a sandblasting operation in which the sandblasting material consists of a substantially homogeneous mixture of silica and oxalic acid crystals in the ratio by weight within the range of 20 to 1 and 40 to 1, the oxalic crystals being capable of passing thRough a screen between 100 and 200 mesh, the silica being capable of passing through a screen of approximately 16 mesh, the sandblasting operation simultaneously eroding the more easily erodible areas and brightening and bleaching the wood surface to simulate the appearance characteristics of material pecky tidewater cypress. 